Local Intra Block Copy Search for Accurate Video Decoding
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing video coding technologies face inefficiencies in predicting motion vectors (MVs) due to rounding errors and statistical likelihood variations, leading to suboptimal compression ratios and increased data requirements.
Innovation Solution
Implementing intra block copy (IBC) techniques that utilize reconstructed samples from a reference block to generate and overwrite collocated sub-blocks, ensuring accurate MV prediction by avoiding overwriting of specific sub-blocks based on their positions, thereby enhancing MV prediction accuracy and reducing data redundancy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of information
If motion vectors are predicted from surrounding MVs using statistical likelihood, then data redundancy is reduced, but rounding errors and statistical variations lead to suboptimal prediction accuracy
Solution Approach 1:
The patent copies reconstructed samples directly from a reference block within the same picture to the current block, bypassing the need for statistical MV prediction. This copying approach eliminates rounding errors while maintaining low data redundancy, as the reference block is already available in the reconstructed picture.
Solution Approach 2:
The reference block is reconstructed and stored in memory before the current block is processed. This preliminary reconstruction ensures that high-accuracy reference samples are available when needed, improving prediction accuracy without requiring complex statistical calculations.
2Measurement precision
If IBC uses a large search range to find reference blocks, then prediction accuracy improves, but computational complexity and processing time increase
Solution Approach 1:
The patent restricts the IBC search to a local reference block within the same picture, typically adjacent to the current block. This local search approach maintains prediction accuracy for locally correlated content while significantly reducing computational complexity compared to global search methods.
Solution Approach 2:
Instead of searching the entire picture for the best reference block, the patent uses a partial search within a limited local region. This partial action is sufficient for most video content where spatial correlation is strongest in nearby areas, avoiding the excessive computational cost of a complete search.
3Quantity of substance
If reconstructed samples are overwritten in memory during IBC, then memory utilization improves, but prediction accuracy deteriorates when reference samples are lost
Solution Approach 1:
The patent performs preliminary reconstruction and stores reference blocks in memory before they are needed for IBC prediction. This ensures reference samples are available and prevents overwriting them with current block data, maintaining prediction accuracy while managing memory efficiently through planned allocation.
Solution Approach 2:
The patent introduces a separate reference block storage area in memory that acts as an intermediary between the reconstruction process and IBC prediction. This intermediary storage prevents reference samples from being overwritten by current block data, ensuring their availability for accurate prediction.
Data Source
AI summary
In a method for video decoding in a decoder, reconstructed samples of a reconstructed block of a picture are stored. When a current sub-block in a current block of the picture is to be reconstructed using intra block copy (IBC) based on a reference sub-block in the reconstructed block, the reference sub-block for the current sub-block is identified, whether the reconstructed samples of the reference sub-block stored are indicated as overwritten is determined based on a position of the current sub-block, reconstructed samples of the current sub-block for output are generated based on the reconstructed samples of the reference sub-block when the reconstructed samples of the reference sub-block stored are determined to be indicated as not overwritten, and the reconstructed samples of a collocated sub-block in the reconstructed block stored are overwritten with the generated reconstructed samples of the current sub-block.